Plasma-driven exsolution-sulfidation creates CoS₂/perovskite heterostructures for flexible zinc-air batteries

Flexible zinc-air batteries (ZABs) are promising power sources for wearable and portable electronics owing to their high energy density, intrinsic safety, and low cost. However, their practical application remains limited by the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air cathode. Here, we develop a plasma-driven one-step exsolution-sulfidation strategy to construct CoS₂/perovskite heterostructures on Sr_1.8Fe_0.5Mo_0.5CoO_6-δ (SFMC) nanofibers. During plasma treatment, Co species are exsolved from the SFMC lattice and simultaneously sulfurized, forming CoS₂ nanoparticles that are firmly anchored on the oxygen-deficient SFMC surface. Experimental results and density functional theory calculations demonstrate that the SFMC/CoS₂ heterointerface induces interfacial charge redistribution, accelerates charge transfer, and lowers the free-energy barriers of OER and ORR. SFMC/CoS₂ exhibits markedly enhanced bifunctional oxygen electrocatalytic activity and enables an all-solid-state flexible ZAB with a peak power density of 247.7 mW cm^-2 and robust cycling stability. This work establishes plasma-driven exsolution-sulfidation as an effective strategy for constructing strongly coupled metal sulfide/perovskite heterostructures for high-performance flexible metal-air batteries.